It’s hardly news that eating meat is a bad idea: it’s long been recognized that the dietary choice is not only damaging to your health, but also a significant driving factor in global warming. However, a new study has detailed another worrying element in meat production – the greenhouse gas emissions from fertilizers used to grow animal feed. The study from the Woods Hole Research Center in Massachusetts, published in Environmental Research Letters, calls for a 50 percent reduction in meat consumption and changes in agricultural practices so as to stem rising emissions of nitrous oxide, reported to be the most potent of all greenhouse gases.

Nitrous oxide isn’t just found in fertilizer, of course. It’s also in manure, and where cows and pigs are concerned, both ends of the process are a significant concern. The Guardian explained: “Growing feed crops, for cattle and pigs, produces more of those [nitrous oxide] emissions than crops that go directly into the human food chain,” and at the current rate, we’re going to be producing a lot more of these emissions.

The report’s author, Eric Davidson, looked at projected population and consumption increase and found that “the 2050 human population of 8.9 billion is projected to have average daily per capita caloric intake of 3130 kcal,” up by 340 calories on 2000. Combined with a projected sharp increase in meat consumption by 2050 to “89kg per person a year in rich countries and 37kg per person a year in the developing world,” would see a significant increase in fertilizer usage, releasing yet more ozone-damaging nitrous oxide into the atmosphere. The report can be read in full here.

So there’s a theoretically simple solution: reduce meat consumption by 50 percent, and make changes in agricultural practices “such as growing winter ground cover crops, [which] would help absorb nitrogen and prevent its release into the atmosphere.” Davidson believes that such measures could offset the potential rise in emissions. In short, if there are more people, then each person should eat less meat.

Speaking to The Guardian, Davidson proposed that “The solution isn’t that everyone needs to become a vegetarian or a vegan. Simply reducing portion sizes and frequency would go a long way.” There are a number of efforts to create meat alternatives that might even entice meat-lovers, though even Davidson admits that it’s an uphill struggle.

But if the issue here is one of reducing our use of fertilizers and consumption of meat, then surely the issue is also one which could be addressed in part by making some kind of dent in our massive food wastage. If, as recent data suggests, 30-50 percent of the world’s food goes uneaten then those “reduced portion sizes” could be the first step to many positive changes.